Summary: Better cardiovascular health in midlife was associated with a decreased risk of developing dementia later in life.
A long-term study of 1,449 people in Finland found that those who had better scores on standard metrics of cardiovascular health in midlife, especially for behavioral factors such as smoking, had a lower risk of dementia later in life.
Yajun Liang of Karolinska Institutet in Stockholm, Sweden, and colleagues present these findings in the open-access journal PLOS Medicine.
Previous research suggests that efforts to address modifiable risk factors, such as behaviors that impact heart health, could reduce the global number of people with dementia by up to one third. However, there is a lack of evidence on potential links between risk of late-life dementia and scores on standard heart health metrics in midlife and late life.
To gain further clarity on late-life risk of dementia, Liang and colleagues analyzed data on 1,449 participants in the Finnish Cardiovascular Risk Factors, Aging and Dementia study, enrolled 1972¬-1987 and assessed in 1998, and 744 dementia-free survivors were followed further into late life (2005¬-2008). Participants’ heart health was evaluated from midlife to late life according to six factors classified as three behavioral (smoking status, physical activity, and body mass index) and three biological factors (fasting plasma glucose, total cholesterol, and blood pressure). Dementia was diagnosed in 61 persons in the first follow up, and additional 47 persons in the second.
The researchers found that participants with intermediate or ideal cardiovascular health scores from midlife onwards, especially for behavioral factors, had a lower risk of dementia later in life than participants with poor scores.
The researchers found no significant overall association between heart health scores measured in late life and risk of dementia. However, when looking specifically at biological factors, ideal scores in late life were actually associated with greater risk of dementia. The authors note that this could be because some biological hallmarks of dementia might overlap with “ideal” scores on these factors, such as lower blood pressure and lower cholesterol. They also note that the major limitations of this study include the lack of data on diet and midlife plasma glucose, and high rate of attrition.
These findings suggest that maintaining lifelong cardiovascular health, particularly in the areas of smoking, exercise, and body mass index, could reduce dementia risk later in life.
Funding: This work was supported in part by grants from the Academy of Finland (number: 278457, recipient: MK; number: 305810, recipient: MK; number: 317465, recipient: MK); the Academy of Finland (number: 334804, recipient: TN) and the Swedish Research Council (number: 2019-02226, recipient: MK) for the EU Joint Program on Neurodegenerative Diseases (JPND) project EURO-FINGERS under the aegis of JPND; the Academy of Finland (number: 291803, recipient: HS) for MIND-AD project; the Swedish Research council for Health, Working Life and Welfare (number: NA, recipient: MK); the Finnish Cultural Foundation (number: NA, recipient: TN); the Juho Vainio Foundation (number: NA, recipient: TN); the Jalmari and Rauha Ahokas Foundation, Finland (number: NA, recipient: TN); Alzheimerfonden Sweden (number: AF556161, recipient: MK); the Alzheimer’s Research and Prevention Foundation (number: NA, recipient: MK), the Center for Innovative Medicine (CIMED) at Karolinska Institutet South Campus (number: NA, recipient: MK); the AXA Research Fund (number: NA, recipient: MK), the Knut and Alice Wallenberg Foundation (number: NA, recipient: MK); Stiftelsen Stockholms sjukhem (number: NA, recipient: MK), Konung Gustaf V:s och Drottning Victorias Frimurarstiftelse (number: NA, recipient: MK), and Hjärnfonden (number: 2015-0217, recipient: MK); the EU Seventh Framework Programme (HATICE) (number: 305374, recipient: MK); and US Alzheimer’s Association (number: NA, recipient: MK). In addition, the work was supported by grants from the Swedish Research Council (number: 2015-02531, recipient: CQ; number: 2017-00740, recipient: CQ; number: 2017-05819, recipient: CQ); the Swedish Foundation for International Cooperation in Research and Higher Education for the Joint China-Sweden Mobility program (number: CH2019-8320, recipient: CQ); and Karolinska Institutet (number: 2018-01854, recipient: CQ; number: 2020-01456, recipient: CQ), Stockholm, Sweden. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.
About this dementia research news
Source: PLOS Contact: Chengxuan Qiu – PLOS Image: The image is in the public domain
Cardiovascular health metrics from mid- to late-life and risk of dementia: A population-based cohort study in Finland
Very few studies have explored the patterns of cardiovascular health (CVH) metrics in midlife and late life in relation to risk of dementia. We examined the associations of composite CVH metrics from midlife to late life with risk of incident dementia.
Methods and findings
This cohort study included 1,449 participants from the Finnish Cardiovascular Risk Factors, Aging, and Dementia (CAIDE) study, who were followed from midlife (baseline from1972 to 1987; mean age 50.4 years; 62.1% female) to late life (1998), and then 744 dementia-free survivors were followed further into late life (2005 to 2008). We defined and scored global CVH metrics based on 6 of the 7 components (i.e., smoking, physical activity, and body mass index [BMI] as behavioral CVH metrics; fasting plasma glucose, total cholesterol, and blood pressure as biological CVH metrics) following the modified American Heart Association (AHA)’s recommendations. Then, the composite global, behavioral, and biological CVH metrics were categorized into poor, intermediate, and ideal levels. Dementia was diagnosed following the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria. Data were analyzed with Cox proportional hazards and the Fine and Gray competing risk regression models. During the follow-up examinations, dementia was diagnosed in 61 persons in 1998 and additional 47 persons in 2005 to 2008. The fully adjusted hazard ratio (HR) of dementia was 0.71 (95% confidence interval [CI]: 0.43, 1.16; p = 0.174) and 0.52 (0.29, 0.93; p = 0.027) for midlife intermediate and ideal levels (versus poor level) of global CVH metrics, respectively; the corresponding figures for late-life global CVH metrics were 0.60 (0.22, 1.69; p = 0.338) and 0.91 (0.34, 2.41; p = 0.850). Compared with poor global CVH metrics in both midlife and late life, the fully adjusted HR of dementia was 0.25 (95% CI: 0.08, 0.86; p = 0.028) for people with intermediate global CVH metrics in both midlife and late life and 0.14 (0.02, 0.76; p = 0.024) for those with midlife ideal and late-life intermediate global CVH metrics. Having an intermediate or ideal level of behavioral CVH in both midlife and late life (versus poor level in both midlife and late life) was significantly associated with a lower dementia risk (HR range: 0.03 to 0.26; p < 0.05), whereas people with midlife intermediate and late-life ideal biological CVH metrics had a significantly increased risk of dementia (p = 0.031). Major limitations of this study include the lack of data on diet and midlife plasma glucose, high rate of attrition, as well as the limited power for certain subgroup analyses.
In this study, we observed that having the ideal CVH metrics, and ideal behavioral CVH metrics in particular, from midlife onwards is associated with a reduced risk of dementia as compared with people having poor CVH metrics. Maintaining life-long health behaviors may be crucial to reduce late-life risk of dementia.